Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisor: Satoshi Tomioka, Dept. of Linguistics. Includes bibliographical references.

<p> Many industries have legacy software systems which are definitely important to them but are however, difficult to maintain due to a lack of understanding of those systems. This occurs as a result of inadequate or inconsistent documentation. Although the costs of redesigning the system may be large, some organizations still plan to reverse engineer the software specification documents from the code to alleviate a large burden from such endeavour. This thesis provides an incremental and modular approach to create a process and tools to extract the semantics of legacy assembly code.</p> <p> Our techniques consist of static analysis and symbolic interpretation in order to reverse engineer the semantics of legacy software. We examine the case of IBM-1800 programs in detail. From the abstract model of the operational semantics of IBM-1800, we simultaneously obtain an emulator and a symbolic analysis process. Augmented with control flow information, we can use the symbolic analysis to provide complete semantics for the code sequences of interest. We can also generate Data Flow Graphs to depict the flow of data in those code segments. The whole process of extracting semantic information from the assembler codes is fully automated with only a little human intervention at the initial step.</p> <p> We use Haskell as our implementation language and its important features help us to create modular and well structured software. The literate programming documentation style in this thesis increases the readability and consistency of the implementation's documentation.</p> <p> The process and the associated tools created in this thesis are used in a large reverse engineering project, which has a goal to extract requirements specification from legacy assembly code. This project is funded jointly by Ontario Power Generation (OPG) and CITO (Communications and Information Technology Ontario).</p> / Thesis / Master of Applied Science (MASc)

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In this dissertation, the traditional dichotic listening paradigm was integrated with the notion of working memory capacity (WMC) to explore the cognitive mechanism of bilingual speech comprehension at the passage level. A bilingual dichotic listening (BDL) task was developed and administered to investigate characteristics of bilingual listening comprehension, which include semantic relatedness, unattended language, ear preference, auditory attentional control, executive control, voluntary note-taking, and language switching. The central concept of the BDL paradigm is that the auditory stimuli are presented in the bilinguals’ two languages and their attention is directed to one of their ears while they have to overcome cognitive and linguistic conflicts caused by information in the other ear. Different experimental manipulations were employed in the BDL task to examine the characteristics of bilingual listening comprehension. The bilingual population examined was Japanese- English bilinguals with relatively high second language (L2) proficiency and WMC. Seven experiments and seven cross-experimental comparisons are reported. Experiment 1 employed the BDL task with pairs of passages that had different semantic relationships (i.e., related or unrelated) and were heard in different languages (i.e., L1 or L2). The semantically related passages were found to interfere with comprehension of the attended passage more than the semantically unrelated passages, whether the attended and unattended languages were the same or different. Contrary to the theories of bilingual language control, unattended L1 was found to enhance comprehension of the attended passage, regardless of semantic relationships and language it was heard in. L2 proficiency and WMC served as good predictors of resolution of the cognitive and linguistic conflicts. The BDL task is suggested to serve as an experimental paradigm to explore executive control and language control in bilingual speech comprehension. Experiment 2 was conducted to investigate language lateralisation (i.e., ear preference) on bilingual speech comprehension, hence, the participants in Experiment 1 used their preferred ear, whereas participants in Experiment 2 used their non-preferred ear, whether it was left or right, in the BDL task. Comprehension was better through the preferred ear, indicating that there is a favourable ear-to-hemisphere route for understanding bilinguals’ two languages. Most of the participants were found to be left-lateralised (i.e., right-eared) and some to be right-lateralised (i.e., left-eared) presumably depending on their L2 proficiency and WMC. Experiment 3 was concerned with auditory attentional control, and explored whether there would be a right-ear advantage (REA). The participants indicated an REA whether the attended and unattended languages were L1 or L2. When they listened to Japanese in the left ear, they found it more difficult to suppress Japanese in the right ear than English. WMC was not required as much as expected for auditory attentional control probably because the passages in Experiment 3 did not yield as much semantic competition as those in Experiment 1. L2 proficiency was crucial for resolving within- and between-language competition in each ear. Experiments 4, 5, and 6 were replications of Experiments 1, 2 and 3, but these latter experiments considered the effect of note-taking that is commonly performed in everyday listening situations. Note-taking contributed to better performance and clearer understanding of the role of WMC in bilingual speech comprehension. A cross-experimental analysis between Experiments 1, 2, 4, and 5 revealed not only a facilitatory role of note-taking in bilingual listening comprehension in general, but also a hampering role when listening through the preferred ear. Experiment 7 addressed the effect of predictability of language switching by presenting L1 and L2 in a systematic order while switching attention between ears and comparing the result with that of Experiment 6 where language switching was unpredictable. The effect of predictability of language switching was different between ears. When language switches were predictable, higher comprehension was observed in the left ear than the right ear, and when language switches were unpredictable, higher comprehension was observed in the right ear than the left ear, thereby suggesting a mechanism of asymmetrical language control. WMC was more related to processing of predictable language switches than that of unpredictable language switches. The dissertation ends with discussions of the implications from the seven BDL experiments and possible applications, along with experimental techniques from other relevant disciplines that might be used in future research to yield additional insight into how bilingual listeners sustain their listening performance in their two languages in the real-life situations.

Speaking a second language requires the ability to keep the two languages apart so that language interference can be avoided, allowing the target language to be used fluently. As such, cognitive control systems are used more extensively in bilinguals compared to monolinguals, a process referred to as bilingual language control (BLC). In the past few decades, the cognitive and structural effects of this lifelong language control experience have been of great interest among researchers within the field of cognitive neuroscience. The present thesis reviews current knowledge on the neural correlates of bilingual language control in high proficient bilingual speakers who actively use both languages in their everyday lives. Language proficiency and frequency of use are important aspects to consider since they both modulate brain activity and structure. Indeed, some studies fail to provide this information. Neuroimaging studies reveal consistent brain activity in a network of cortical and subcortical areas in bilingual speakers during non-verbal and verbal executive control tasks. These brain areas include the anterior cingulate cortex (ACC), prefrontal cortex (PFC), inferior parietal lobes (IPLs), basal ganglia (BG) and the cerebellum. Research also indicates that bilingualism serves as a protective variable against age-related cognitive decline. Studying the effects of lifelong bilingualism on the brain has therefore proven to be important since it can influence an individual’s ability to cope with age decline at a cognitive level.

One of the main findings of research on bilingualism in the last twenty years is the fact that both languages are always active, to some extent, and interact with each other. This interaction gives rise to a computationally complex feature of the bilingual mind, namely that the two languages compete with each other. Many studies have addressed the linguistic consequences of this competition (e.g. differences in linguistic attainment), while others have instead addressed the cognitive consequences (e.g. training effects on cognitive control). These two strands of research, when brought together, can shed light on the dynamics of language processing and of its relationship with other cognitive abilities; however, they do not often converge. The first aim of this thesis is to seam them together. The second aim of this thesis is to understand the effects of specific aspects of language experience on linguistic and non linguistic abilities. A critical assumption I make is that bilingualism is not a dichotomous variable, but rather a continuum, characterised by several aspects such as linguistic proficiency, age of acquisition, and daily exposure. All of these factors interact with each other to give rise to potentially infinite types of bilingual experiences, and arguably modulate how bilinguals deal with competing languages. However, the effects of these factors on linguistic and non linguistic abilities are poorly understood. Hence, in this thesis I examine if the bilingual experience affects other cognitive abilities (study 1), how the ability to handle this competition is modulated by experience (study 2), and how it affects language processing (study 3). To examine how specific dimensions of the bilingual continuum affect these abilities, I compare four populations of bilinguals, whose linguistic experience ranges from late bilinguals who are immersed in their native language and are passive users of their second language, to early highly proficient bilinguals who use both languages actively. My first study examines cognitive control performance and shows that high active proficiency and early age of acquisition, together, represent beneficial circumstances for the ability to modulate cognitive control; however, their effects are not strong enough to override individual variability. The second study investigates how the bilingual experience modulates the ability to access the two languages separately, overcoming the competition between them at different levels. This could be at a local level, i.e. the level of the individual linguistic representation (e.g. naming time of a specific word), or at a global or whole language level (e.g. overall naming latencies across languages). The results show that proficiency affects local competition, and age of acquisition affects global competition, whereas daily language exposure regulates competition at both the local and the global levels. My third study examines the processing of pronouns, which are particularly demanding linguistic structures. It shows that active proficiency and age of acquisition, together, define circumstances in which pronoun processing may vary between individuals, independently of structural differences between their languages. This suggests that bilinguals with long-term exposure to more than one language and high active proficiency may use some linguistic structures in the same way as individuals with different linguistic backgrounds, i.e. explicitly interpret them in similar ways, but process them in marginally different ways. Through these studies, this thesis brings together research on linguistic and cognitive aspects of bilingualism by identifying three dimensions of the bilingual experience - proficiency, exposure and age of acquisition - and their effects on language processing, language control and cognitive control.

On estime que plus de la moitié de population mondiale sait parler au moins deux langues et que 40% de cette population bilingue utilise les deux langues au quotidien. Les psycholinguistes et les neuropsycholinguistes se sont rapidement intéressés au fonctionnement du cerveau bilingue et à la façon dont deux langues pouvaient partager un seul cerveau. Ainsi, de nombreuses recherches ont porté sur la représentation de plusieurs langues dans le cerveau ainsi que sur les mécanismes permettant de passer d’une langue à l’autre, mais aussi sur la période développementale sensible à l’apprentissage des langues.Dans ce travail, nous nous sommes intéressés au rôle de l’âge d’acquisition et du niveau de compétence des deux langues sur a) la représentation des substrats cérébraux, b) la plasticité cérébrale et c) la capacité d’alterner entre les deux langues. Pour cela nous comparons des locuteurs bilingues précoces -qui ont appris les deux langues avant 3 ans- et des locuteurs bilingues tardifs -qui ont appris la deuxième langue après 10 ans- tous ayant atteint un très bon niveau de compétence dans les deux langues. Le niveau langagier et le fonctionnement exécutif des participants ont été mesurés à l’aide de plusieurs tâches linguistiques et non linguistiques. Grâce à la technique d’imagerie par résonances magnétiques fonctionnelles (IRMf), nous avons pu identifier les substrats neuronaux des deux langues pour chacun des groupes, les aires impliquées dans le contrôle des langues ainsi que les changements cérébraux dus à l’apprentissage précoce de deux langues. De manière générale, les résultats montrent que la compétence langagière, plutôt que l’âge d’acquisition, aurait un rôle essentiel sur la représentation des langues. En revanche, l’âge d’acquisition serait déterminant en ce qui concerne la structure cérébrale des certaines aires impliquées dans les processus langagiers. / It is estimated that more than half of the world's population speaks two languages and that 40% of the population uses both languages on a daily basis. Psycholinguists and neuropsycholinguists became interested early in the way in which two languages could share a single brain. They have therefore been interested in the representation of several languages in the bilingual brain, in the sensitive period during which languages are learned and also in the mechanisms that allow bilinguals to switch from one language to another without apparent effort. In this work, we investigated the role of the age of acquisition and proficiency of languages and the influence of two languages a) on the representation of cerebral substrates of two languages, b) on the cerebral plasticity, c) and on the mechanisms of language control. For this purpose, we compare early bilingual speakers, who learned both languages before the age of 3 years, and late bilingual speakers who learned the second language after 10 years, both of whom had a very good level of proficiency in both languages. Participants were assessed in a wide range of linguistic and non-linguistic tasks to measure language level and executive functioning. Using the functional magnetic resonance imaging technique, we were able to identify the neuronal substrates of the two languages for each group and the areas involved in language control, as well as cerebral changes due to the early learning of two languages. In general, the results show that language proficiency, rather than the age of acquisition, has an essential role on the representation of languages, but that the age of acquisition is decisive in regards of cerebral structure of certain areas related to language.

abstract: Mild TBI (mTBI) has been associated with subtle executive function (EF) and cognitive-communication deficits. In bilinguals, there are unique cognitive demands required to control and process two languages effectively. Surprisingly, little is known about the impact of mTBI on EF, communication, and language control in bilinguals. Therefore, the aim of this study was to examine the cognitive-communication abilities in bilinguals with a history of mTBI, identify any language control impairments, and explore the relationship between these language control impairments and domain-general cognitive control abilities. To this end, three-hundred and twenty-seven monolingual and bilingual college students with and without mTBI history participated in two experiments. In these experiments, EF, communication, and language control were examined using experimental and clinical tasks as well as self-rating scales. In Experiment 1, there was an interaction between mTBI history and language group (monolinguals vs. bilinguals) in how participants performed on a clinical measure of EF and a verbal fluency task. That is, only bilinguals with mTBI scored significantly lower on these tasks. In addition, there was a significant correlation between errors on a language switching task and performance on non-verbal EF tasks. In Experiment 2, a subgroup of bilinguals with persistent cognitive and behavioral symptoms reported greater everyday communication challenges in their first and second languages. Also, unbalanced bilinguals reported greater EF difficulties than monolinguals and balanced bilinguals regardless of mTBI history. In conclusion, bilinguals may face unique cognitive-communication challenges after mTBI. Factors related to the bilingual experience (e.g., language balance, daily language use) should be considered in clinical evaluation and future research. / Dissertation/Thesis / Doctoral Dissertation Speech and Hearing Science 2020

This essay presents an interventional field study that aims to refine practice in the English classroom in Swedish upper-secondary school by implementing imitation pedagogy. Imitation pedagogy is essentially learning to analyze and imitate texts’ internal structure for developing one’s own production. The focus on my first research question was on examining if imitation pedagogy with political mentor texts develop students’ language awareness, language control, and argumentative abilities in reading and writing. My second research question was focused on investigating if political mentor texts could be used to prepare students for future participation in civic discussions and debates. My initial hypothesis was that mentor texts with political topics in imitation pedagogy could be used to develop students’ argumentative abilities; the learners could through this pedagogy be taught to recognize linguistic features in political texts that aim to persuade audiences, and the learners could learn to imitate these mentor texts to produce own successful argumentative writing. To answer my research questions and to see if my hypothesis was accurate, I conducted an interventional field study that followed a lesson study model. The findings from my study indicate that imitation pedagogy does develop and enhance learners’ language awareness, argumentative abilities, and ability to provide stronger contributions to discussions in different social and democratic contexts. Imitation pedagogy enhances the learners’ confidence and improve their writing capabilities, specifically the ability to compose stronger argumentations in writing in different situations varying from smaller everyday issues to larger societal and political issues. Moreover, imitation pedagogy promotes the development of language control and critical language awareness. The learners practiced writing in new patterns, which forced the students to use their linguistic knowledge to produce sentences with language accuracy, fluency, and coherency. In addition, the students learned in this interventional study to recognize different linguistic and grammatical features that can add power to written compositions in different social and democratic contexts. By being able to recognize these features, the learners can be more aware of manipulative language in political texts and more effectively counter them.

How do bi/multilinguals switch between languages so effectively that there is no obvious intrusion from the alternatives? One can examine this by comparing language selection with task selection, or language switching with task switching. This is the approach adopted in the first of two strands of research presented in this thesis. In task switching, providing advance warning of the task typically leads to a reduction in the performance ‘switch cost’, suggesting top-down biasing of task selection. It is not clear whether the language switch cost also reduces with preparation, partly because there have been very few attempts to examine preparation for a language switch, and partly because these attempts suffered from non-trivial methodological drawbacks. In Experiments 1-3 I used an optimised picture naming paradigm in which language changed unpredictably and was specified by a language cue presented at different intervals before the picture. Experiment 1, conducted on ‘unbalanced’ bilinguals, revealed some evidence of reduction in the language switch cost for naming times with preparation, but only when cue duration was short. In an attempt to further optimise the paradigm, in Experiment 2 the cue-stimulus interval (which was varied from trial to trial in Experiment 1), was varied over blocks instead. Visual cues were replaced with auditory cues – the latter also enabled a comparison between semantically transparent word cues (the spoken names of the languages) and less transparent cues (fragments of national anthems). Experiment 2 revealed a reduction in switch cost with preparation for naming latencies, but only in the second language; the first language showed the reverse. To examine whether the increase in switch cost with preparation in the first language could be due to unbalanced bilinguals biasing processing towards L2, balanced bilinguals were tested in Experiment 3. This revealed a robust reduction in switch cost in naming latencies for both languages, which was driven primarily by the trials with the anthem cues. However, in the error rates the switch cost increased with preparation interval, thus complicating the interpretation of the reduction observed for response times. Experiment 4 investigated whether preparation for a language switch elicits the electrophysiological patterns commonly found during preparation for a task switch – a switch-induced positive polarity Event-Related Potential (ERP) with a posterior scalp distribution. Contrary to a recent report of the absence of the posterior positivity in language switching, it was clearly present in the present EEG data. As in task switching, the amplitude of the posterior positivity predicted performance. The electrophysiological data suggest that preparation for a language switch and preparation for a task switch rely on highly overlapping control mechanisms. The behavioural data suggest that advance control can be effective in language switching, but perhaps not as effective as in task switching. Experiments 1-3 also examined the effect of stimulus associative history – whether the language used on the previous encounter with a given stimulus influenced performance on the current trial). Having previously named a given picture in the same language benefited overall performance, but did not do so more for switches than repeats. Thus, stimulus associative history does not seem to contribute to the language switch cost. The second strand of my research asked whether bilinguals can set themselves independently for speech vs. comprehension. Previous research has examined the cost of switching the language in output tasks and in input tasks. But, it is not clear whether one can apply separate control settings for input and output selection. To investigate this, I used a paradigm that combined switching languages for speech production and comprehension. My reasoning was that, if there is cross-talk between the control settings for input vs. output, performance in one pathway should benefit if the language selected for the other pathway is the same relative to when it is different: a ‘language match effect’. Conversely, if there is no cross-talk, there should not be a language match effect. In Experiment 5 bilinguals alternated predictably between naming numbers in their first and second language (in runs of 3 trials), whilst also having to semantically categorise spoken words which occasionally (and unpredictably) replaced the numbers. The language of the categorisation ‘probes’ varied over blocks of ~17 naming runs, but was constant within a block. The results showed a clear match effect in the input task (categorisation), but not the output task (naming). To examine the potential role of proficiency, Experiment 6 used the same paradigm to test unbalanced and balanced bilinguals. The pattern of results was qualitatively similar in both groups to that observed in Experiment 5: a language match effect confined to the input task. These results suggest ‘leakage’ from the output control settings into the input control settings.